Beyond transcription, aryl hydrocarbon receptor plays a protective role in periodontitis by interacting with CaMKII.

BACKGROUND: The aryl hydrocarbon receptor (AhR) has been studied as an intracellular pattern recognition receptor that can identify bacterial pigments. To identify a potential therapeutic target for periodontitis, we investigated the expression of AhR in periodontitis and its role in the pathogenesis of periodontitis. METHODS: First, we analyzed AhR expression in a single-cell dataset from human periodontal tissue. Quantitative polymerase chain reaction (qPCR), immunofluorescence, and immunohistochemistry were used to verify the AhR level. Later, we determined the phenotypes of ligature-induced periodontitis in myeloid-specific AhR-deficient mice (Lyz2-Cre+/- AhRfx/fx), after which RNA sequencing (RNA-seq), qPCR, Western blot, immunofluorescence, and immunohistochemistry were used to investigate the impacts of AhR on periodontitis and its mechanism. Finally, we determined the therapeutic effect of AhR agonist 6-Formylindolo[3,2-b]carbazole (FICZ) administration on murine periodontitis and verified the effects of FICZ on macrophage polarization in vitro. RESULTS: AhR expression was enhanced in macrophages from periodontitis patients. Deletion of AhR from macrophages aggravated ligature-induced periodontitis and promoted the inflammatory response. Calcium/calmodulin-stimulated protein kinase II (CaMKII) phosphorylation was accelerated in AhR-deficient macrophages. Inhibiting CaMKII phosphorylation ameliorated periodontitis in Lyz2-Cre+/- AhRfx/fx mice. FICZ treatment blocked alveolar bone loss and relieved periodontal inflammation. FICZ diminished M1 macrophage polarization and promoted M2 macrophage polarization upon M1 macrophage induction. CONCLUSION: AhR played a protective role in the pathogenesis of periodontitis by orchestrating macrophage polarization via interacting with the CaMKII signaling pathway.

BBR affects macrophage polarization via inhibition of NF-κB pathway to protect against T2DM-associated periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis is intimately associated with the development of various systemic diseases, among which type 2 diabetes mellitus (T2DM) has a bidirectional relationship with the pathogenesis of periodontitis. The objective of the present work was to investigate the role of berberine (BBR) in periodontitis with T2DM and related mechanisms. METHODS: The mRNA expression of macrophage polarization-related factors in the microenvironment of periodontal inflammation was detected using real-time quantitative PCR (RT-qPCR). The experimental periodontitis model was constructed in wild-type (WT) and T2DM (db/db) mice, which were administered BBR after 7 days of modeling. Alveolar bone loss (ABL) in each group of mice was measured utilizing micro-computed tomography images. RT-qPCR was performed to analyze the levels of macrophage polarization-related factors in mouse gingiva. Lastly, using western blotting and RT-qPCR, the signaling pathway of BBR affecting macrophage polarization in the microenvironment of periodontitis was explored. RESULTS: BBR inhibited M1 polarization and stimulated M2 polarization in the periodontitis microenvironment. BBR decreased ABL in the WT and T2DM periodontitis models. And BBR reduced the production of proinflammatory cytokines and increased anti-inflammatory cytokine expression in the gingiva of WT and T2DM model mice. Ultimately, BBR mediates its anti-inflammatory effects on periodontitis through inhibition of the NF-κB pathway. CONCLUSIONS: BBR had a therapeutic effect on T2DM-associated periodontitis via inhibiting the NF-κB pathway to affect macrophage polarization, which may have implications for the new pharmacological treatment of T2DM-associated periodontitis.

Arrestin beta-2 deficiency exacerbates periodontal inflammation by mediating activating transcription factor 6 activation and abnormal remodelling of the extracellular matrix.

AIM: To investigate the specific role of arrestin beta-2 (ARRB2) in the progression of periodontitis and the underlying mechanisms. MATERIALS AND METHODS: Single-cell RNA sequencing data were used to analyse gene expression in periodontal tissues from healthy controls and patients with periodontitis. Real-time quantitative polymerase chain reaction, Western blotting and immunohistochemical staining were performed to detect the expression of ARRB2. Furthermore, a ligature-induced periodontitis model was created. Using radiographic and histological methods, RNA sequencing and luciferase assay, the role of ARRB2 in periodontitis and the underlying mechanisms were explored. Finally, the therapeutic effect of melatonin, an inhibitor of activating transcription factor 6 (ATF6), on periodontitis in mice was assessed in both in vivo and in vitro experiments. RESULTS: ARRB2 expression was up-regulated in inflammatory periodontal tissue. In the ligature-induced mouse model, Arrb2 knockout exacerbated alveolar bone loss (ABL) and extracellular matrix (ECM) degradation. ARRB2 exerted a negative regulatory effect on ATF6, an essential targeted gene. Melatonin ameliorated ABL and an imbalance in ECM remodelling in Arrb2-deficient periodontitis mice. CONCLUSIONS: ARRB2 mediates ECM remodelling via inhibition of the ATF6 signalling pathway, which ultimately exerts a protective effect on periodontal tissues.

miR-27a-5p alleviates periodontal inflammation by targeting phosphatase and tensin homolog deleted on chromosome ten.

INTRODUCTION: MicroRNAs (miRNAs), a type of non-coding RNA, have been demonstrated to be essential posttranscriptional modulators in oral diseases and inflammatory responses. However, the specific role of miR-27a-5p in periodontitis requires further investigation. In this study, we used both cellular and animal models to determine how miR-27a-5p affects the pathogenesis of periodontitis and its associated biological functions. METHODS: Quantitative real-time polymerase chain reaction and western blotting were used to analyze the expression of cytokines, phosphatase and tensin homolog deleted on chromosome ten (PTEN), and miR-27a-5p transcription. Investigation of alveolar bone resorption and inflammation of the periodontium in ligature-induced periodontitis in mice was performed using micro-computed tomography (micro-CT), hematoxylin-eosin (HE) staining, and tartrate-resistant acid phosphatase (TRAP) staining. The binding of miR-27a-5p and PTEN was predicted using the TargetScan database and experimentally confirmed using dual luciferase reporter gene assays. RESULTS: The inflamed gingiva showed lower levels of miR-27a-5p. Macrophages from miR-27a-5p-/- mice produced much higher quantities of pro-inflammatory cytokines owing to the stimulation of Porphyromonas gingivalis lipopolysaccharide, and miR-27a-5p-/- mice with ligature-induced periodontitis also exhibited more severe alveolar bone resorption and damage to the periodontium. Target validation assays identified PTEN as a direct target of bona. Blocking PTEN expression partially reduced inflammation, both in vitro and in vivo. CONCLUSIONS: miR-27a-5p alleviated the inflammatory response in periodontitis by targeting PTEN.